Improvement in mechanical telephones



H. WILLARD 8L A. M. CHENEY.

Mechanical Telephone.

Pate nted Jan. 21, 1879.

UNITED STATES PATENT OEEIoE HENDERSON \VILLARD AND ALONZO M. CHENEY, OF CHARLOTTE, MIOH.

lMPROVEMENT IN MECHANICAL TELEPHONES.

Specificationiorniing part of Letters Patent No. 211,486, dated January 21, 1879; application filed October 16, 1878.

To all whom it may concern:

Be it known that we, HENDERSON WIL- LARD and ALONZO M. CHENEY, both of Charlotte, Eaton county, in the State of Michigan, have invented a certain new and useful improvement in Acoustic or Mechanical Telephones, of which the following is a full and suflicient specification, reference being had to the accompanying drawings and letters of reference marked thereon.

Like letters in the different figures mean the same thing.

The trouble with acoustic telephones heretofore has been that the reverberations drown the articulate sounds, or render them too indistinct for practical use.

E e have overcome this difticulty by eonstructing our telephone of solid wood, using no other vibrating material.

All are more or less familiar with the peculiar acoustic properties of wood. The ticking of a watch or the articulate sounds of the voice may be distinctly heard throughout the longest stick of timber.

One mode of carrying out our invention is to turn a cup or funnel in the side or end of a solid block of wood, in such a manner that the bottom of the cup shall form the diaphragm of the instrument; or the cup may be turned entirely through the block, and the diaphragm of wood glued onto the solid walls of the cup. (See Figure 1, in which 1* is the tunnel or cup, M is the diaphragm, and L is the line or wire connecting it with a similar instrument at a distant oflice.) The block is ten inches square and two inches thick, more or less. The eup bottem is four inches in diameter, and the diaphragm is from one-sixteenth to onefourth of an inch in thickness, according to the distance between offices connected by the line. 'lfthe distance is short, the thicker one is better; but, for the sake of most perfect results, we hin getwo instruments together, one with thick diaphragm for receiver and the other with thin diaphragm for speaker, and in such a manner that the operator can speak in one and receive in the other without turning, as shown in Fig. 2, in which A is the receiver, andB is the speaker, and G is a short line connecting speaker 13 with main line L, which is anchored fast to the diaphragm of receiver A.

After speaking in B the operator swings it back, which slackens its line C, and the answer comes directly to A, and is received privately; but if speaker 13 is left in full tension the message can be heard by many.

Any kind of wood is suitable for these instruments; but ash or walnut is preferable, and they can be made externally round or angular and ornamented to suit taste.

e do not claim, broadly, the use of a wooden box as a sounder or receiver, as we know that cigar-boxes have long been used for the same purpose.

hat we do claim as new, and wish to secure by Letters Patent, is

1. An acoustic-telephone instrument coir sisting of a cup or funnel in the end or side of a solid block of wood, so that the bottom of the cup shall form the transmitting or receivin g diaphragm, substantially as set forth.

2. The combination of the transmitting and receiving diaphragms and their frames, hinged together at the sides, as shown, so that they may be turned in position to receive and transmit sounds to the operator at the same time.

HENDERSON XVILLARD. ALONZO M. CHENEY. Witnesses:

Emsrm STEWART, J. M. lln'sLnfnr. 

